Scorch extending curing/crosslinking compositions
AssigneeElf Atochem North America, Inc.
InventorsMichael Fred Novits, Chester Joseph Kmiec, Edward Phillip Hibbard
Life of this patent
Estimating the term…
Abstract
A crosslinkable composition of a polymeric thermoplastic and/or elastomeric material which is susceptible to scorching when processed at elevated temperatures, prior to crosslinking, in the presence of a free radical initiator, is protected against such scorching by the incorporation therein of a mixture of at least one hydroquinone compound and a sulfur accelerator. This mixture may also contain at least one monomeric allylic, methacrylic, acrylic or diene type coagent. The mixture exhibits a synergistic effect resulting in improved scorch protection for peroxide cured systems when compared with the protection afforded by the components singly.
Claims20
An improved composition for retarding scorch during the compounding of thermoplastic polymers curable with organic peroxides, elastomeric polymers curable with organic peroxides and mixtures of said polymers in the presence of free radical initiators selected from the group consisting of dialkyl peroxides or diperoxy ketals, said improved composition being prepared by mixing as the essential ingredients:
- a) sulfur accelerator selected from the group;
- (i) compounds represented by the structure:
- ##STR4## wherein X is an ion derived from a metal selected from the group consisting of nickel, cobalt, iron, chromium, tin, zinc, copper, lead, bismuth, cadmium, selenium and tellurium, n may vary from 1 to 6 and is equal to the formal valance of the metal ion and R.sub.1 and R.sub.2 are independently alkyl of 1 to 7 carbon atoms;
- (ii) sulfenamides;
- and
- (iii) compounds represented by the structure:
- ##STR5## wherein R.sub.3 is an alkyl group of 1 to 7 carbon atoms and n may have a positive value of from greater than zero up to about 6;
- b) hydroquinone in a weight ratio of 1:50 to 500:1 to sulfur accelerator;
- and
- c) coagent in a weight ratio of 100:1 to 1:100 by weight based on total weight of hydroquinone and sulfur accelerator, wherein the coagent is selected from the group consisting of monofunctional vinyl monomers, monofunctional allyl monomers, polyfunctional vinyl monomers, polyfunctional allyl monomers and mixtures thereof.
Dependencies are inferred from the claim text.